JAPAN | EDITORIAL: Nuclear power plant ‘stress tests’ must be transparent

Posted on July 7, 2011



The government has decided to carry out “stress tests” on all nuclear power plants in Japan to assess their safety.

To be relevant and reliable now, such safety tests must be based on lessons learned from the accident at the Fukushima No. 1 nuclear plant triggered by the Great East Japan Earthquake in March. They must not be mere rituals to declare the facilities safe.

The plan to conduct the safety tests was announced July 6 by Banri Kaieda, minister of economy, trade and industry.

Kaieda apparently hopes the tests will pave the way for restarting the reactors currently out of service for regular safety checks before demand for power peaks in midsummer. They include the Nos. 2 and 3 reactors at the Genkai nuclear power plant in Saga Prefecture.

But the stress tests launched by the EU in response to the Fukushima nuclear disaster are exhaustive probes covering a wide range of natural and man-made disasters, such as earthquakes, tsunamis and various terrorist attacks including the intentional crashing of planes into nuclear power plants. The EU tests are designed to examine whether the plants can safely cool the reactors to a state of shutdown in such situations.

We support the introduction of similar stress tests on nuclear plants in Japan, if they are intended as a means to boost the actual safety of the facilities.

It is impossible, of course, to conduct such full-scale stress tests in time for this summer.

What is vital is to secure the credibility and reliability of the tests as a measure to evaluate the safety of nuclear power plants.

The planned stress tests will be conducted mainly with computer simulations. They will measure the facilities’ overall margins of resistance to assumed disasters.

The effectiveness of the tests depends on such factors as how the capabilities and geotectonic environments of the nuclear power plants are properly quantified and whether the assumptions concerning the impacts of presumed incidents are reasonable.

The tests will be conducted basically by the plant operators, according to the government’s plan, because they have most of the necessary data.

In the wake of crisis at the Fukushima plant, the government’s Nuclear and Industrial Safety Agency ordered all nuclear power stations in Japan to take emergency safety measures.

But the agency swiftly pronounced all the facilities to be safe despite wide differences among them in age and geographical and geological conditions. This move only deepened the distrust of the nuclear regulators by residents living in areas around the facilities.

The government needs to ensure transparency of the planned stress tests by publishing not just the results but also all the assumptions and procedures involved.

The government also has to offer convincing answers, along with reasonable grounds, to such crucial questions as how the minimum margin of safety required for nuclear power plants is determined and what to do with the plants that are judged not to meet the standards.

The government must consider seriously how it can regain the trust of the public.

A vital question for the government’s efforts to restore the credibility of the nuclear safety regulations is who supervises the industry.

It is necessary to establish quickly an independent regulatory and supervisory organization with sufficient expertise that is dedicated to ensuring the safety of nuclear facilities. The Nuclear and Industrial Safety Agency of the industry ministry, which has been promoting nuclear power generation, should be replaced by the new institution as the regulator of the nuclear power industry.

The EU’s safety tests will be subject to peer review by multinational teams of experts in the final stage. This is to prevent the rigorousness of the tests from being compromised by insider favoritism.

In order to avoid social confusion due to a power shortage, it is necessary to resume the operation of the currently suspended reactors that are deemed safe.

This policy imperative requires the government to make sure that the stress tests will gain credibility with both the anxious local residents and the international community, which are paying close attention to Japan’s responses to the nuclear disaster.

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